Thomas E. Lauer

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---We investigated the response of the mottled sculpin Cottus bairdi and the johnny darter Etheostoma nigrum to the invasion and proliferation of the round goby Neogobius melanostomus at three near-shore locations in southern Lake Michigan. Fish were collected by trawling from June through August, 1984 to 2002. Mean annual catches of mottled sculpins in(More)
Pharmaceuticals and personal care products (PPCPs) have been documented throughout the United States freshwaters but research has focused largely on lotic systems. Because PPCPs are designed to have a physiological effect, it is likely that they may also influence aquatic organisms. Thus, PPCPs may negatively impact aquatic ecosystems. The objectives of(More)
The trophic linkage between yellow perch Perca flavescens and two exotic prey items, alewife Alosa pseudoharengus and round goby Neogobius melanostomus, was investigated in the extreme southern area of Lake Michigan during the summer of 2002. Yellow perch 100mm total length, LT (n1⁄4 1293) exhibited size selective feeding, with 148 fish containing round(More)
Few studies have addressed within-year temporal variation of IBI scores. We compared index of biotic integrity (IBI) scores for two summer sampling events from a large river during 25 annual periods. The results indicated that IBI scores calculated from June samples were not significantly different from July samples. Spatial autocorrelation was present,(More)
Two years of fish assemblage data from 28 sites in the Wabash River Indiana, were examined for relationships with environmental variables using a multivariate approach, correspondence analysis. Upstream sites had lower mean daily discharge and lower coefficient of variation of daily discharge when compared to downstream sites. Although the fish assemblage(More)
Bluegill Lepomis macrochirus and green sunfish Lepomis cyanellus were examined using geometric morphometrics to evaluate the variation in morphology between fishes that reside in lentic (e.g. lakes) and lotic (e.g. streams) ecosystems. Live fishes were collected from reservoirs and rivers in central Indiana, while additional fishes were sampled from museum(More)
Species interactions between two types of sessile benthic invertebrates, the zebra mussel (Dreissena polymorpha) and freshwater sponges (Porifera), were evaluated in Michigan City IN Harbor in southern Lake Michigan during 1996. The study objective was to define whether competition plays a role in structuring benthic communities using experimental(More)
Size-selective harvest of fish stocks can lead to maturation at smaller sizes and younger ages, which may depress stock productivity and recovery. Such changes in maturation may be very slow to reverse, even following complete fisheries closures. We evaluated temporal trends in maturation of five Great Lakes stocks of yellow perch (Perca flavescens(More)